Existing computing environments use virtual storage which is normally maintained in auxiliary storage to increase the size of available storage. When a page of virtual storage is referenced, the virtual address used in referencing the page is translated by dynamic address translation to a real storage address. If the translation is successful, then the virtual storage is valid; otherwise, it is invalid. A page of virtual storage is indicated as valid or invalid by an invalid bit in a page table entry, which entry includes a real storage address if the page is valid.
Pages of storage can be invalidated a page at a time. For instance, in a computing environment based on the z/Architecture, offered by International Business Machines Corporation, an instruction, referred to as an Invalidate Page Table Entry (IPTE) instruction, is used to invalidate a page of storage. Invalidation includes setting an invalid indicator in a control structure, associated with virtual storage and located in physical main storage, to indicate that a virtual address of a location in the virtual storage cannot be translated by dynamic address translation to a physical main storage address, also called a real address. Further, the instruction is used to clear internal machine buffer entries associated with the page, which entries may be used during dynamic address translation to avoid accessing the control structures in physical main storage. For instance, in the z/Architecture, there are Translation Lookaside Buffers used during dynamic address translation of virtual addresses to real addresses. When a page of storage is invalidated, the corresponding buffers are also cleared of entries associated with that page.
There are also instructions that enable the purging of entire Translation Lookaside Buffers. For instance, in the z/Architecture, an instruction, referred to as a Compare and Swap and Purge (CSP) instruction, purges all entries of Translation Lookaside Buffers.
Thus, although there are instructions to invalidate a page of storage and clear buffers of entries associated with that page, and instructions to clear entire buffers, there still exists a need for instructions that can selectively invalidate various sizes of units of storage and/or clear buffers of entries associated therewith. For example, a need exists for an instruction that enables the specification of a selected unit of storage greater than a page to be invalidated and/or have buffer entries associated therewith cleared. A further need exists for an instruction that enables the clearing of buffer entries for selected units of storage, without affecting buffer entries for other units of storage.